A device according to the invention is intended to provide assistance in the placement of modules in an environment, the latter possibly being a cavity such as a well, or else an aquatic environment such as the ocean. One particular application of the invention relates to borehole wells. During the course of drilling or exploiting borehole wells, it is generally sought to model the environment around the well, this being done by the geophysical surveying thereof.
In order to do this, seismic probes (constituting modules) are lowered into the well at various successive depths. These probes are conventionally in the form of tubular elements and are equipped with measuring instrumentation intended for studying the geological formations encountered or for carrying out seismic prospecting. These probes are joined together by an electromechanical cable including electrical distribution lines for the instrumentation and signal transmission lines. For informational purposes, the tubular elements commonly have a length of approximately 0.6 meters (and can reach 1.7 m for the largest modules) and the cables have a length of approximately 15 m.
The assembly formed by the cables and the probes is, for example, a “VSP” (Vertical Seismic Profile) chain or any other chain of seismic acquisition modules, and constitutes a heterogeneous system within the meaning of the invention. In other words, a system such as this is designated as heterogeneous in the sense that it consists of components of different shapes and dimensions (e.g., the probes, rigid lengthwise, and the cables, flexible and having a small cross-sectional area in comparison with the probes), involving guide members for their take-up/deployment, which are customized to each component.
Currently, the probes are lowered one-by-one into the borehole wells, their connection to the cables being carried out as the VSP chain descends. Of course, the operations for assembling the probes together with the cables require considerable holding time and, furthermore, are carried out on site under conditions that may in practice be non-optimal (in particular due to the overall dimensions of the worksite, climatic conditions, etc.). Furthermore, mechanical testing of the assembly is itself carried out as the VSP descends, this testing generally being ensured by the persons having been engaged in the assembly. Of course, this self-testing is carried out with the greatest of care. But, the personnel in charge of these operations is also subjected to productivity considerations, motivating them to work at a steady pace, which can be a source of errors and therefore malfunctions.
Such being the case, it is observed that, in practice, once the chain is in place, a break in the transmission of data is often detected, rendering the chain overall inoperable. This can be due to the failure of one of the components of the chain/or to the faulty connection of one of the components with the cables. This failure can be localized at the level of the first components lowered into the well, and is only detected once the complete chain has been installed. It may then be necessary to pull the chain out completely in order to perform checks, and to then re-install the chain once the detected defects have been corrected.
Furthermore, current VSP chains include a relatively limited number of probes, between 2 and 32. As far as the chains with 32 probes are concerned, they can have a length of several hundred meters, which involves considerable installation (or removal) time. Such being the case, chains capable of comprising up to 100 levels have recently been proposed.
It is understood that the time for placing the VSP chains inside the wells (as well as that for removing them from the well) will be substantially increased due to the increase in the number of probes and operations for connecting them to the cables. It is further noted that the increase in the number of probes in the VSP chains tends to weigh down the storage and/or transport logistics for the various components of the chain.
There is a need for improved material handling arrangements, and particularly there is a need for material handling equipment that addresses the disadvantages of existing systems.